Higgs boson mass constraints from precision data and direct searches

Abstract

Two of the nine measurements of ${\mathrm{sin}}^{2}\ensuremath{\theta}{}_{\mathrm{eff}}^{\mathrm{lepton}},$ the effective weak interaction mixing angle, are found to be in significant conflict with the direct search limits for the standard model (SM) Higgs boson. Using a scale factor method, analogous to one used by the Particle Data Group, we assess the possible effect of these discrepancies on the SM fit of the Higgs boson mass. The scale factor fits increase the value of ${\mathrm{sin}}^{2}\ensuremath{\theta}{}_{\mathrm{eff}}^{\mathrm{lepton}}$ by as much as two standard deviations. The central value of the Higgs boson mass increases as much as a factor of 2, to $\ensuremath{\simeq}200 \mathrm{G}\mathrm{e}\mathrm{V},$ and the 95% confidence level upper limit increases to as much as 750 GeV. The scale factor is based not simply on the discrepant measurements, as was the case in a previous analysis, but on an aggregate goodness-of-fit confidence level for the nine measurements and the limit. The method is generally applicable to fits in which one or more of a collection of measurements are in conflict with a physical boundary or limit. In the present context, the results suggest caution in drawing conclusions about the Higgs boson mass from the existing data.